This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. TSG-6, the secreted product of tumor necrosis factor-stimulated gene-6, is composed of a Link module and a CUB module domain. The Link module is involved in binding to glycosaminoglycans and the entire system is in someway involved in remodeling the extracellular matrix. This is a process that normally occurs in response to injury of blood vessels but also occurs in rheumatoid arthritis and osteo-arthritis. The particular glycosaminoglycans to which the TSG-6 Link module binds include hyaluronan, heparan sulfate and chondroitin sulfate, but it appears that the binding sites might be different and interact allosterically. Professor Day has supplied the plasmid and expression advice on this glycosaminoglycan-binding protein. The Resource is providing the chondroitin sulfate oligomers and the NMR expertise to structurally define the binding mode. The project will use specialized orientational constraints developed in the Resource to facilitate structure determination.